There are many types of laundry additive materials suitable for use in automatic washing machines for fabric laundering. Cleaning agents such as surfactants and detergent builders are used to assist in the mechanical removal of soil and stains from fabrics being laundered. Bleaching agents, enzymes and adjuvants relating thereto are designed to promote chemical degradation and removal of soils and stains. Fabric conditioners, softeners, anti-wrinkle agents, soil release materials and similar agents serve to alter and enhance the condition, appearance or feel of laundered fabrics. Other auxiliary materials, such as pH adjustment and control agents, buffers, solvents, dispersants, anti-redeposition agents, dye transfer inhibitors, stabilizers, preservatives, perfumes, dyes and the like are used to alter the aqueous environment in the automatic washing machine drum to provide for optimum performance of the active laundry additive materials or to improve the quality or aesthetics of commercialized laundry products containing these active additive materials.
The several types of laundry additive materials described hereinbefore, frequently intermingled or admixed together in a wide variety of combinations for convenience, are commonly marketed to consumers in bulk quantities, in either solid, i.e., granular or tablet, or liquid form. To carry out the laundering operation, the consumer then adds aliquots of product as needed or desired from the bulk products into the automatic washing machine drum in appropriate amounts and at appropriate times during the laundering cycle.
It would be desirable, and a number of attempts have been made, to market fabric laundering products in “unit dose” form whereby aliquots of combinations of laundry additive materials are provided in pre-measured, pre-packaged form. The consumer can then conveniently add one of these unit dose aliquots to the automatic washing machine, e.g., into the drum, at the beginning of the laundry cycle and not have to measure product from bulk or add product to the cycle at different subsequent points in time.
Several factors complicate the provision of multiple types of laundry additive materials in unit dose form. In the first place, many types and forms of laundry additives are not compatible with each other within a single concentrated product. Different types of materials may chemically interact with each other when admixed in concentrated form, thereby degrading and rendering one or both types ultimately ineffective for its intended purpose. Such incompatibility works against combining such materials together within a single unit dose product.
Secondly, during the laundering cycle itself, different types of laundry additives work best under different conditions which occur as the laundering operation progresses through its cycle which generally includes washing and one or more rinsing stages within the drum. It therefore becomes advantageous to add different types of laundry additives to the washing machine drum at different times during the laundering cycle. This timed or staged addition of separate, distinct materials to the automatic washing machine drum is also difficult to accomplish with product packaged in unit dose form.
Given the foregoing difficulties in formulating unit dose products for use in fabric laundering operations carried out in a multi-cycle, drum-containing automatic washing machine, it would be desirable to provide a system which can effectively utilize laundry additive products in unit dose form to deliver a variety of ingredients to the drum of an automatic fabric laundering machine during its operational cycle. This is realized by providing a unit dose in the form of a package having one or more compartments that is placed into a housing unit that is positioned within the washing machine drum and which serves to bring about selective dispensing of laundry additives from the one or more compartment(s) of the insert.